Thrombopoietin receptor agonist for treatment of immune thrombocytopenia in pregnancy: a narrative review

ITP in pregnancy: diagnostics and therapeutics in 2024

Thrombocytopenia will occur in 10% of pregnancies-ranging from the clinically benign to processes that can threaten both mother and fetus. Accurately identifying the specific etiology and appropriate clinical management is challenging due to the breadth of possible diagnoses and the potential of shared features among them. Further complicating diagnostic certainty is the lack of confirmatory testing for most possible pathophysiologies. Immune thrombocytopenia (ITP) is recognized in less than 0.1% of pregnancies but is the most common cause of thrombocytopenia in early trimesters. ITP is an autoimmune disease of IgG-mediated enhanced platelet clearance and reduced platelet production. While there is an increasing number of drugs approved to treat ITP and more being examined in clinical trials, few have been sufficiently studied in pregnancy, representing a major unmet need in clinical practice. As such, treatment options for ITP in pregnancy are limited to corticosteroids and immunoglobulin therapy, which will not be effective in all cases. Maternal ITP also may have fetal impact, and any proposed therapeutic intervention must account for this possibility. Optimal care requires multidisciplinary collaboration between hematology, obstetrics, and anesthesia to enhance diagnostic clarity, develop an optimized treatment regimen, and shepherd mother and neonate to delivery safely.

Isolated thrombocytopenia in pregnancy: A monocentric retrospective study of 63 pregnancies in 59 women

Thrombocytopenia during pregnancy is often thought to be associated with severe bleeding manifestations. Three are the main disorders associated with this condition: gestational thrombocytopenia (GT), immune thrombocytopenia (ITP), and inherited thrombocytopenias (ITs). Reaching the correct diagnosis of this condition has relevant therapeutic and outcome implications. We performed a retrospective, observational, monocentric study enrolling 59 consecutive women with isolated thrombocytopenia, attended to our referral center in the last 3 years. Together with personal and family history, platelet (PLT) count trend and mean platelet volume (MPV) in pregnancy are helpful for the diagnosis, with the highest PLT count in GT and lowest in ITs, with different timing of count decrease. MPV is significantly increased in both ITs and ITP. Misdiagnosis with ITP was responsible for unnecessary and unsuccessful therapy in some GT or ITs pregnant women, determining relevant side effects. Excluding inherited platelet function disorders (IPFDs), the bleeding risk for mother with thrombocytopenia and their newborns is similar to the general population. Vaginal delivery is associated with a lower risk of bleeding than cesarean section and therefore is preferable whenever obstetrical-gynecological conditions permit.

Navigating Primary Immune Thrombocytopenia During Pregnancy With Management Strategies and Considerations: A Comprehensive Review

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a reduction in platelet count due to autoantibody-mediated platelet destruction. ITP presents unique challenges during pregnancy, affecting both maternal and fetal health. This comprehensive review explores the pathophysiology, diagnosis, and management strategies of ITP in pregnant women, emphasizing the importance of individualized care. The incidence of ITP in pregnancy is significant, with potential complications including maternal hemorrhage and neonatal thrombocytopenia. Effective management is crucial to minimize these risks and ensure optimal outcomes. First-line treatments typically include corticosteroids and intravenous immunoglobulin (IVIG), with second-line options such as immunosuppressive agents and thrombopoietin receptor agonists. This review highlights the significance of multidisciplinary care and the need for careful monitoring and adjustment of treatment plans based on the severity of thrombocytopenia and the pregnancy stage. This review aims to enhance clinical decision-making and improve maternal and fetal outcomes in pregnancies complicated by ITP by providing a detailed analysis of current practices and emerging therapies.

Repeat dose and reproductive toxicity of thrombopoietin mimic peptide in Sprague-Dawley rats

Thrombopoietin mimic peptide (TMP) is a novel thrombopoietin receptor agonist. In this report, we evaluated the potential toxicity of TMP in repeat-dose toxicity and reproductive/developmental toxicity studies (segment Ⅰ, Ⅱ, Ⅲ). TMP was administered subcutaneously to Sprague-Dawley (SD) rats at 5, 15 or 50 mcg/kg. In repeat-dose toxicity study, the rats were administrated three times a week for 26 week with a 4-week recovery. TMP could produce anti-drug antibodies and induce platelet counts increase, megakaryocyte proliferation. While platelet counts decreased gradually and returned to normal after 4 weeks in male rats. Other significant findings included myelofibrosis of bone marrow, hepatic extramedullary hematopoiesis, splenic lymphocytic depletion and bone hyperostosis. All treatment-related effects were reversed following recovery. The NOAEL of repeat-dose toxicity in female rats is 5 mcg/kg. In the reproductive/developmental toxicity (segment Ⅰ, Ⅲ), no deaths occurred, and no general toxicological effects or abnormal reproductive functions were observed. In embryo-fetal developmental toxicity study (segment Ⅱ), the number of resorbed fetuses in the 50 mcg/kg group was significantly increased. The NOAEL as related to reproductive/developmental toxicity in these rats was 15 mcg/kg.

How I treat thrombocytopenia in pregnancy

ABSTRACT

Thrombocytopenia is a common hematologic abnormality in pregnancy, encountered in ∼10% of pregnancies. There are many possible causes, ranging from benign conditions that do not require intervention to life-threatening disorders necessitating urgent recognition and treatment. Although thrombocytopenia may be an inherited condition or predate pregnancy, most commonly it is a new diagnosis. Identifying the responsible mechanism and predicting its course is made challenging by the tremendous overlap of clinical features and laboratory data between normal pregnancy and the many potential causes of thrombocytopenia. Multidisciplinary collaboration between hematology, obstetrics, and anesthesia and shared decision-making with the involved patient is encouraged to enhance diagnostic clarity and develop an optimized treatment regimen, with careful consideration of management of labor and delivery and the potential fetal impact of maternal thrombocytopenia and any proposed therapeutic intervention. In this review, we outline a diagnostic approach to pregnant patients with thrombocytopenia, highlighting the subtle differences in presentation, physical examination, clinical course, and laboratory abnormalities that can be applied to focus the differential. Four clinical scenarios are presented to highlight the pathophysiology and treatment of the most common causes of thrombocytopenia in pregnancy: gestational thrombocytopenia, preeclampsia, and immune thrombocytopenia.

An Innovative Inducer of Platelet Production, Isochlorogenic Acid A, Is Uncovered through the Application of Deep Neural Networks

(1) Background: Radiation-induced thrombocytopenia (RIT) often occurs in cancer patients undergoing radiation therapy, which can result in morbidity and even death. However, a notable deficiency exists in the availability of specific drugs designed for the treatment of RIT. (2) Methods: In our pursuit of new drugs for RIT treatment, we employed three deep learning (DL) algorithms: convolutional neural network (CNN), deep neural network (DNN), and a hybrid neural network that combines the computational characteristics of the two. These algorithms construct computational models that can screen compounds for drug activity by utilizing the distinct physicochemical properties of the molecules. The best model underwent testing using a set of 10 drugs endorsed by the US Food and Drug Administration (FDA) specifically for the treatment of thrombocytopenia. (3) Results: The Hybrid CNN+DNN (HCD) model demonstrated the most effective predictive performance on the test dataset, achieving an accuracy of 98.3% and a precision of 97.0%. Both metrics surpassed the performance of the other models, and the model predicted that seven FDA drugs would exhibit activity. Isochlorogenic acid A, identified through screening the Chinese Pharmacopoeia Natural Product Library, was subsequently subjected to experimental verification. The results indicated a substantial enhancement in the differentiation and maturation of megakaryocytes (MKs), along with a notable increase in platelet production. (4) Conclusions: This underscores the potential therapeutic efficacy of isochlorogenic acid A in addressing RIT.

Knowledge map of thrombopoietin receptor agonists: A bibliometric analysis

Thrombopoietin receptor agonists (TPO-RAs) have been widely used to treat thrombocytopenia, however, a scientometric profile of TPO-RAs research is lacking. Methods: This study uses VOSviewer, CiteSpace, and R software to provide an overview of current research, highlight study hotspots, and predict future research directions of TPO-RAs. Results: One thousand seven hundred and nineteen relevant studies from 1993 to 2022 with 43962 citations were identified from the Web of Science Core Collection. Over three decades, the USA has been leading TPO-RAs publications. Industries and academic institutions have been actively involved in TPO-RAs research, with funding provided by pharmaceutical companies and public funding bodies. The most productive and cited journals are British Journal of Hematology and Blood, respectively. When author keywords were categorised into three clusters, i.e., cluster 1 (immune thrombocytopenic purpura (ITP)), cluster 2 (avatrombopag, lusutrombopag, and thrombocytopenia), and cluster 3 (TPO-RAs for ITP and off-label drug use), ITP was found to be the current research hotspot, while oral TPO-RAs and licensed or unlicensed drug indications of thrombocytopenic diseases require further investigation. Conclusion: This study has generated the knowledge map of TPO-RAs, which provides a dynamic roadmap for future research in this field.

Avatrombopag, a promising novel thrombopoietin receptor agonist for refractory/relapsed/intolerant non-severe aplastic anemia: a phase 2 single-arm clinical trial

INTRODUCTION

The therapeutic options for thrombocytopenia in non-severe aplastic anaemia (NSAA) are limited. Avatrombopag (AVA) is prescribed for thrombocytopenic diseases but not for NSAA.

METHODS

Herein, we conducted a phase 2, non-randomized, single-arm trial to explore the efficacy and safety of AVA in refractory/relapsed/intolerant NSAA. AVA dose was initiated at 20 mg/d and titrated to a maximum of 60 mg/d. The primary endpoint was the haematological response at 3 months.

RESULTS

Twenty-five patients were analyzed. The overall response rate (ORR) at 3 months was 56% (14/25), with 12% (3/25) achieving a complete response (CR). At a median follow-up of 7 (3-10) months, the OR and CR rates were 52% and 20%, respectively. Responders had a shorter duration of diagnosis of AVA administration than non-responders (10 (6-80) vs 37 (6-480) months, p = 0.027) and belonged to the relapsed/intolerant NSAA type (71% vs 27%, p = 0.047); 44% (8/18) patients previously treated with eltrombopag before enrollment responded at 3 months, with an average prior eltrombopag dose of median 72.5 (50-100) mg/d and an average AVA dose for a response of median 43.5 (20-60) mg/d. 3-month ORR had no significant correlation with eltrombopag exposure (p = 0.09), prior eltrombopag length (R²=0.11), or cumulative eltrombopag dose (R²=0.30). Only one patient relapsed after stopping AVA for 1 month. No serious AVA-related side effects or clone evolution were detected.

CONCLUSION

AVA is effective and well-tolerated in NSAA patients who are refractory, relapsed, or intolerant to CsA/tacrolimus ± eltrombopag. Earlier treatment and relapsed/intolerant AA may show a better short-term response rate. More studies are needed to define the optimal dose and the long-term efficacy (NCT04728789).

Evaluating circulating soluble markers of endothelial dysfunction and risk factors associated with PE: A multicentre longitudinal case control study in northern Ghana

Serpin E1/PAI-1, N-terminal pro-brain natriuretic peptide (NTpro-BNP) and neuropilin-1 are markers which have been associated with endothelial dysfunction. However, data on the levels of these markers in PE is limited. The limited data on the pathophysiology of PE in relation to these markers necessitated the study. This was a multicentre case-control study conducted at the Obstetrics and Gynaecology Department of the Tamale Teaching Hospital, the Bawku Presbyterian Hospital and the Bolgatanga Regional Hospital. Out of 520 consenting pregnant women, 127 pregnant women met the inclusion criteria (53 with PE and 74 controls) and were included in this study. Venous, placental, cord and peripheral blood were collected for biomarker assay, haematological parameters and placental parasite determination. Placental tissue sections were obtained for placental malaria and histopathological lesions associated with hypoperfusion. Maternal heart rate and foetal umbilical artery Doppler impedance indices; resistance index (RI) and systolic diastolic (SD) ratio were determined to confirm utero-placental hypoperfusion. Significantly higher proportions of foeto-maternal complications; eclampsia, low birth weight (LBW), neonatal intensive care unit admissions (NICU), intrauterine growth restriction (IUGR), caesarian deliveries and early gestational age at delivery were associated with PE. Women with PE had lower concentrations of platelet (p = 0.02) whereas red cell distribution width (RDW) was markedly elevated (p = 0.01). NTPro-BNP concentration was markedly elevated (p = 0.01) in women with PE whereas neuropilin-1 concentration was lower (p = 0.03) compared to the non-PE group. Maternal heart rate was elevated in women with PE and Doppler resistance indices (RI and SD) were significantly elevated in foetuses of PE women than foetuses of the controls. Placental mal-perfusion lesions were higher in women with PE compared to the non-PE group. Women with PE had increased risk of adverse foeto-maternal complications, significantly associated with placental mal-perfusion lesions, had reduced platelet concentration and elevated RDW-CV levels. NTPro-BNP, RI and SD are elevated in women with PE whereas neuropilin-1 concentration is reduced. Significant changes in these pathological variables in PE women is indicative of significant derangement in endothelial function culminating in adverse maternal and perinatal outcomes of pregnancy.

Application of recombinant human thrombopoietin in pregnant women with immune thrombocytopenia: a single-center experience of four patients and literature review

The management of pregnant women with immune thrombocytopenia who fail to respond to corticosteroids and intravenous immunoglobulin is an intractable clinical challenge because of the limited availability of evidence-based information. Recombinant human thrombopoietin (rhTPO) is recommended for refractory immune thrombocytopenia (ITP). To date, however, few studies have investigated rhTPO treatment during pregnancy. We retrospectively reviewed four cases who were diagnosed with ITP and treated with rhTPO during pregnancy in our center from January 2015 to June 2020. Of the four cases, two (50%) responded to rhTPO treatment. No adverse events were noted in the newborns. Our findings indicate that rhTPO treatment is safe for patients with refractory gestational ITP, and that subcutaneous injection is a convenient delivery method that does not lead to adverse events. Thus, rhTPO may be a viable alternative treatment option for patients with refractory gestational ITP who do not respond to first-line therapies.

Trends in outcomes and racial disparities in adult hospitalizations for immune thrombocytopenia over a decade

Immune thrombocytopenia (ITP) is a diagnosis of exclusion characterized by a low platelet count in patients for whom other etiologies have been ruled out. It occurs due to autoimmune-mediated platelet destruction and thrombopoietin deficiency. ITP is a rare hematologic disorder in adults, and scarce information exists on the hospitalization outcomes among these patients. To address this knowledge gap, we conducted a nationwide population-based study from 2010 to 2019 using the National Inpatient Sample. We found a trend toward an increase in the annual admissions for ITP (from 392.2 to 417.3, p = 0.07). There was a decrease in mortality exclusively for White patients over the period studied (p = 0.03), which was not seen in Black or Hispanic patients. There was an increase in total charges adjusted for inflation for all subgroups (p < 0.01). Length of stay decreased during the decade analyzed (p < 0.01) for the total population and most subgroups. The rates of epistaxis and melena increased (p < 0.01), while rates of intracranial hemorrhage and hematemesis did not change significantly. Advances have been made in the ITP management over the past decade. However, this has not resulted in a decrease in the number of hospitalizations or total healthcare charges during hospitalization. Furthermore, a decrease in mortality was observed in White patients but not in other races. Prospective studies are needed to better characterize the financial burden of the disease, as well as to investigate racial variability in access to care, disease behavior, and response to treatment.

Use of thrombopoietin receptor agonists in adults with immune thrombocytopenia: a systematic review and Central European expert consensus

There are currently three thrombopoietin receptor agonists (TPO-RAs) approved in Europe for treating patients with immune thrombocytopenia (ITP): romiplostim (Nplate®), eltrombopag (Revolade®), and avatrombopag (Doptelet®). However, comparative clinical data between these TPO-RAs are limited. Therefore, the purpose of this study was to perform a literature review and seek expert opinion on the relevance and strength of the evidence concerning the use of TPO-RAs in adults with ITP. A systematic search was conducted in PubMed and Embase within the last 10 years and until June 20, 2022. A total of 478 unique articles were retrieved and reviewed for relevance. The expert consensus panel comprised ITP senior hematologists from eight countries across Central Europe. The modified Delphi method, consisting of two survey rounds, a teleconference and email correspondence, was used to reach consensus. Forty articles met the relevancy criteria and are included as supporting evidence, including five meta-analyses analyzing all three European-licensed TPO-RAs and comprising a total of 31 unique randomized controlled trials (RCTs). Consensus was reached on seven statements for the second-line use of TPO-RAs in the management of adult ITP patients. In addition, the expert panel discussed TPO-RA treatment in chronic ITP patients with mild/moderate COVID-19 and ITP patients in the first-line setting but failed to reach consensus. This work will facilitate informed decision-making for healthcare providers treating adult ITP patients with TPO-RAs. However, further studies are needed on the use of TPO-RAs in the first-line setting and specific patient populations.

Thrombocytopenia in pregnancy

Hematologists are often consulted for thrombocytopenia in pregnancy, especially when there is a concern for a non-pregnancy-specific etiology or an insufficient platelet count for the hemostatic challenges of delivery. The severity of thrombocytopenia and trimester of onset can help guide the differential diagnosis. Hematologists need to be aware of the typical signs of preeclampsia with severe features and other hypertensive disorders of pregnancy to help distinguish these conditions, which typically resolve with delivery, from other thrombotic microangiopathies (TMAs) (eg, thrombotic thrombocytopenic purpura or complement-mediated TMA). Patients with chronic thrombocytopenic conditions, such as immune thrombocytopenia, should receive counseling on the safety and efficacy of various medications during pregnancy. The management of pregnant patients with chronic immune thrombocytopenia who are refractory to first-line treatments is an area that warrants further research. This review uses a case-based approach to discuss recent updates in diagnosing and managing thrombocytopenia in pregnancy.

Prednisone plus IVIg compared with prednisone or IVIg for immune thrombocytopenia in pregnancy: a national retrospective cohort study

BACKGROUND

The responses of intravenous immunoglobulin (IVIg) or corticosteroids as the initial treatment on pregnancy with ITP were unsatisfactory. This study aimed to assess the safety and effectiveness of prednisone plus IVIg versus prednisone or IVIg in pregnant patients with immune thrombocytopenia (ITP).

METHODS

Between 1 January 2010 and 31 December 2020, 970 pregnancies diagnosed with ITP at 19 collaborative centers in China were reviewed in this observational study. A total of 513 pregnancies (52.89%) received no intervention. Concerning the remaining pregnancies, 151 (33.04%) pregnancies received an initial treatment of prednisone plus IVIg, 105 (22.98%) pregnancies received IVIg alone, and 172 (37.64%) pregnancies only received prednisone.

RESULTS

Regarding the maternal response to the initial treatment, no differences were found among the three treatment groups (41.1% for prednisone plus IVIg, 33.1% for prednisone, and 38.1% for IVIg). However, a significant difference was observed in the time to response between the prednisone plus IVIg group (4.39 ± 2.54 days) and prednisone group (7.29 ± 5.01 days; p  < 0.001), and between the IVIg group (6.71 ± 4.85 days) and prednisone group (p < 0.001). The median prednisone duration in the monotherapy group was 27 days (range, 8-195 days), whereas that in the combination group was 14 days (range, 6-85 days). No significant differences were found among these three treatment groups in neonatal outcomes, particularly concerning the neonatal platelet counts. The time to response in the combination treatment group was shorter than prednisone monotherapy. The duration of prednisone application in combination group was shorter than prednisone monotherapy. The combined therapy showed a lower predelivery platelet transfusion rate than IVIg alone.

CONCLUSION

These findings suggest that prednisone plus IVIg may represent a potential combination therapy for pregnant patients with ITP.

Bleeding complications associated with pregnancy with primary immune thrombocytopenia: a meta-analysis

Introduction  Immune thrombocytopenia (ITP) during pregnancy has received little attention from researchers. Reliable information about the outcome of mothers and newborns is required to properly counsel women who are pregnant or planning to become pregnant. Our primary outcomes were the frequency and severity of maternal and neonatal bleeding events in the setting of ITP in pregnancy. Mode of delivery, neonatal thrombocytopenia, and maternal/infant mortality were secondary outcomes.

Material and Methods  We comprehensively reviewed the prospective studies that enrolled ≥20 pregnant women with primary ITP. Two reviewers, blinded to each other, searched Medline and Embase up to February 2021. Meta-analyses of the maternal and newborn outcomes were performed. Weighted proportions were estimated by a random-effects model.

Results  From an initial screening of 163 articles, 15 were included, encompassing 1,043 pregnancies. The weighted event rate for bleeding during pregnancy was 0.181 (95% confidence interval [CI], 0.048–0.494). Most of these were nonsevere cases. The weighted event rates were 0.053 (95% CI, 0.020–0.134) for severe postpartum hemorrhage, 0.014 (95% CI, 0.008–0.025) for intracerebral hemorrhage, and 0.122 (0.095–0.157) for severe thrombocytopenia events in neonates (platelet count <50,000/μL). There were no reliable predictors of severe neonatal thrombocytopenia. The incidence of neonatal mortality was 1.06%. There were no maternal deaths.

Conclusion  Primary ITP in pregnant women is rarely associated with poor outcomes.

Aplastic Anemia Treated with Eltrombopag during Pregnancy

Aplastic anemia is a rare blood disorder characterized by pancytopenia and hypocellular bone marrow. In patients with aplastic anemia, pancytopenia sometimes worsens during pregnancy, and relapse of aplastic anemia in pregnancy is common. Nevertheless, only supportive care with blood products is the mainstay of treatment of aplastic anemia in pregnancy. Thus, the obstetric management and treatment of aplastic anemia in pregnancy is extremely challenging. We herein report the first case of a pregnant woman complicated with aplastic anemia who was successfully treated with eltrombopag, a thrombopoietin receptor agonist. A 27-year-old primigravida woman who had a history of aplastic anemia refractory to immunosuppressive therapy and was treated with eltrombopag became pregnant. Eltrombopag treatment was continued after weighing the benefits and potential risks. Throughout pregnancy, the woman's pancytopenia did not progress, and she delivered a 2336 g baby vaginally at 38 weeks of gestation. Her postpartum outcome was uneventful, and the neonate did not develop thrombocytosis. Since the efficacy and safety of eltrombopag in pregnancy has not yet been established, its routine use should be avoided. However, if limited to refractory cases and with adequate maternal and fetal monitoring, including neonatal blood examinations, the use of eltrombopag for patients with aplastic anemia during pregnancy may be acceptable and result in favorable maternal and fetal outcomes.

Effect of Thrombopoietin Receptor Agonist on Pregnant Mice

Thrombopoietin receptor agonists (TPO-RAs) are an effective treatment for refractory immune thrombocytopenia (ITP). However, the use of TPO-RAs is limited for ITP in pregnant women due to concerns about fetal toxicity. In this study, we examined the effects of romiplostim, one of the TPO-RAs, on pregnant mice. The mice were injected subcutaneously with romiplostim (1, 5, 10, 30, and 100 μg/kg) on gestational days (GD) 1, 8, and 15. We evaluated maternal and fetal platelet and megakaryocyte counts (MK), fetal weight at birth, placental morphology, and miscarriage rates. Romiplostim increased platelet and MK counts in pregnant mice at all doses and in fetuses at doses above 10 µg/kg. Fetal weight at birth was slightly reduced at a dose of 100 μg/kg, but there were no significant differences in placental weight, spiral artery wall thickness, placental growth factor signal changes, or the rate of resorption at that dosage. The dose of romiplostim used clinically for ITP patients (1–10 μg/kg) did not show any adverse effects on pregnant mice. Although the results of the present study are encouraging, until there are more conclusive data, the use of romiplostim should be evaluated individually in severe, life-threatening cases, and all relevant ethical aspects should be considered.

Thrombopoietin Receptor Agonists (TPO-RAs): Drug Class Considerations for Pharmacists

The thrombopoietin receptor agonists (TPO-RAs) romiplostim, eltrombopag, avatrombopag, and lusutrombopag carry unique US Food and Drug Administration (US FDA)- and European Medicines Agency (EMA)-approved indications and may be used to increase platelet counts in a variety of conditions. Current indications for available TPO-RAs include treatment of chronic immune thrombocytopenia (ITP) in cases of insufficient response to prior treatment (avatrombopag, eltrombopag, romiplostim), management of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure (avatrombopag, lusutrombopag), management of severe aplastic anemia (eltrombopag), and management of thrombocytopenia associated with interferon-based therapy for hepatitis C (eltrombopag). Across current indications, pharmacists can assist in stabilizing platelet counts and help to reduce large undulations commonly seen when starting, stopping, or transitioning between these agents. If therapy modifications may benefit the patient, pharmacists should discuss possible changes with the patient's treatment team or treating physician. When used for ITP, romiplostim, eltrombopag, and avatrombopag stimulate TPO receptors on hematopoietic stem cells (also known as c-Mpl, or CD110) to promote platelet production; however, romiplostim is the only TPO-RA that binds at the same site as endogenous TPO. These subtle mechanistic differences may explain why switching TPO-RA may be clinically advantageous in some situations. As pharmacists are called to counsel patients on TPO-RA use, a deep understanding of potential adverse events and management strategies, as well as appropriate monitoring, will increase the likelihood that patients meet their goals of therapy in the shortest timeframe. Other uses of TPO-RAs are also discussed in this review, including use following hematopoietic stem cell transplant, use in myelodysplastic syndrome, and use in chemotherapy-induced thrombocytopenia.